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An experimental study on CL2 mechanism of Langmuir circulation

Research Project

Project/Area Number 15540424
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Meteorology/Physical oceanography/Hydrology
Research InstitutionHiroshima Institute of Technology

Principal Investigator

MIZUNO Shinjiro  Hiroshima Institute of Technology, Civil Engineering, Professor, 工学部, 教授 (80033835)

Co-Investigator(Kenkyū-buntansha) MIZUNO Shinjiro  Hiroshima Institute of Technology, Civil Engineering, Professor (80033835)
Project Period (FY) 2003 – 2004
Project Status Completed (Fiscal Year 2004)
Budget Amount *help
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2003: ¥3,100,000 (Direct Cost: ¥3,100,000)
KeywordsAir-sea interaction / Wave-mean current interaction / Organized motion / Langmuir circulation / CL2 Mechanism / Wave-induced Reynolds shear stress / Wind-driven current / Langmuir循環流 / CL2機構
Research Abstract

Laboratory experiments have been undertaken to understand the wave-current interaction under the wind waves. The primary purpose is to answer the following question. How do swell waves interact with the wind-driven current in a wind tank? The effects of swell (monochromatic mechanical waves) on the subsurface flow were examined to test the validity of the CL2 mechanism proposed by Craik (1977) and Leibovich (1977). In order to explore the response of the wind-driven flow to mechanical-waves, we used two sets of mechanical waves : One is referred to as the wind-following swell (case FS), and the other the wind-opposing swell (case OS). For this purpose, a vertical cross-sectional plane normal to the wind was systematically and in detail measured both vertically and laterally using a two-component LDV in each of the 2 sets of swell cases of FS and OS under the action of a constant wind speed of 7-8 m/s.
A strong wave-current interaction was found in a tank flow when the propagation direct … More ion of mechanical-waves (wave frequency = 1Hz, initial wave amplitude H_0 = 2.5 cm) was reversed. First, for case OS the mechanical-waves highly speeded up the primary circulation in the tank but slightly decayed a pair of 2-dimensional (vertical) Langmuir circulation (2D-LC). Second, for case AS they dramatically slowed down the primary circulation, but enhanced the 2D-LC, leading to the generation of vigorous vertical mixing.
First, it is found that the response of the vertical circulation to the monochromatic swell wave is consistent with the CL2 mechanism ; that is, the 2D-LC is enhanced by the wind-following swell but attenuated by the wind-opposing swell. In particular, it tamed out that the wind-following swell caused vigorous turbulent mixing in the whole flow, leading to the slowdown of the primary circulation, which appears to be characteristic of the CL2 mechanism.
Second, the swell-induced Reynolds shear stress was negative in case FS but became positive in case OS. This fact appears to be closely related to the slowdown in case FS and the speedup in case OS of the primary circulation. That is, we may conclude that the swell-induced Reynolds shear stress plays an important role in the acceleration and deceleration of the primary circulation, when it is positive and negative, respectively. Less

Report

(3 results)
  • 2004 Annual Research Report   Final Research Report Summary
  • 2003 Annual Research Report
  • Research Products

    (17 results)

All 2004 2003 2002 Other

All Journal Article (14 results) Publications (3 results)

  • [Journal Article] 波と吹送流の問の相互作用2004

    • Author(s)
      水野 信二郎
    • Journal Title

      日本流体力学会年会2004講演論文集 23巻別冊

      Pages: 30-31

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] 造波機による波を風波の場に与えると、波は流れと如何に相互作用するか2004

    • Author(s)
      水野 信二郎
    • Journal Title

      乱流研究の異分野融合と新たな創成 15ME-S4

      Pages: 171-178

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Annual Research Report 2004 Final Research Report Summary
  • [Journal Article] 波と流れの相互作用に関する実験結果とその力学機構2004

    • Author(s)
      水野 信二郎
    • Journal Title

      乱流研究の異分野融合と新たな創成 16ME-S4

      Pages: 169-176

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Annual Research Report 2004 Final Research Report Summary
  • [Journal Article] Interaction between waves and wind-driven current (In Japanese)2004

    • Author(s)
      Shinjiro Mizuno
    • Journal Title

      Proceeding of 2004 meeting of Japan Society of Fluid Mechanics 23 special

      Pages: 30-31

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] How do wave interact with the wind-driven current? (In Japanese)2004

    • Author(s)
      Shinjiro Mizuno
    • Journal Title

      Trans-Discipline and Innovatio of Approach to Turbulent Phenomena 15ME-S5

      Pages: 171-178

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] The mechanism of wave-current interaction (In Japanese)2004

    • Author(s)
      Shinjiro Mizuno
    • Journal Title

      Trans-Discipline and Innovatio of Approach to Turbulent Phenomena 16ME-S4

      Pages: 169-176

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] 波と吹送流の間の相互作用2004

    • Author(s)
      水野 信二郎
    • Journal Title

      日本流体力学会年会2004 講演論文集 23巻別冊

      Pages: 30-31

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Laboratory experiments on the effects of mechanically Generated waves on the core flow under wind waves2003

    • Author(s)
      Shinjiro Mizuno
    • Journal Title

      Asian and Pacific Coasts 2003 (PDF-File APAC022) 2

      Pages: 1-12

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Annual Research Report 2004 Final Research Report Summary
  • [Journal Article] 造波機による波が風波下の平均流と乱流構造に与える効果に関する実験2003

    • Author(s)
      水野 信二郎
    • Journal Title

      日本流体力学会年会2003講演論文集 22巻別冊

      Pages: 40-41

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Laboratory experiments on the effects of mechanically generated waves on the core flow under wind waves2003

    • Author(s)
      Shinjiro Mizuno
    • Journal Title

      Asian and Pacific Coasts 2003, (PDF-File APAC 022) 2

      Pages: 1-12

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Effects of mechanically generated waves on the mean flow and turbulence (In Japanese)2003

    • Author(s)
      Shinjiro Mizuno
    • Journal Title

      Proceeding of 2003 meeting of Japan Society of Fluid Mechanics 22 special

      Pages: 40-41

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] 造波機による波が風波下の平均流と乱流構造に与える効果に関する実験2003

    • Author(s)
      水野 信二郎
    • Journal Title

      日本流体力学会年会2003 講演論文集 22巻別冊

      Pages: 40-41

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Effects of Counter-swell on both the mean current and Turbulent structure below the wind-waves.2002

    • Author(s)
      Shinjiro Mizuno
    • Journal Title

      Gas transfer at water surfaces 5

      Pages: 115-120

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Effects of Counter-swell on both the mean current and turbulent structure below the wind-waves2002

    • Author(s)
      Shinjiro Mizuno
    • Journal Title

      Gas transfer at water surfaces 5

      Pages: 115-120

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Publications] 水野信二郎, 原田真仁: "造波機の波が風波下の平均流と乱流構造に与える効果について"平成15年度土木学会中国支部 研究発表会発表概要集. 55. 115-116 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] S.Mizuno: "Laboratory experiments on the effects of mechanically generated waves on the core flow under wind waves"Proceedings of Asian and Pacific Coasts 2003. 2. 52-53 (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] 水野信二郎: "造波機による波が風波下の平均流と乱流構造に与える効果に関する水槽実験"日本流体力学会年会 2003 講演論文集. 22. 40-41 (2003)

    • Related Report
      2003 Annual Research Report

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Published: 2003-04-01   Modified: 2016-04-21  

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